One of the numerous problems that have long plagued manufacturers of items that fold or telescope into a compact size for easy storage or portability, is how to store long straight bars; and especially those of adjustible length.
One common method used, is to have consecutively smaller diameter, concentric tubes, that fit inside each other, with means for locking the tubes in an extended position, such as friction type collars or tabs. Because of the required overlap in tubes needed for structural strength, the outer tube contributes most to the extended length, while each consecutive inner tube contributes a consecutively smaller length. The problem is, that when this method is used in items, it results in a long thin unit, which is not very easy to store or carry, as would be an item, for example, having the same volume, but being only half as long.
Another example is a small, compact, folding luggage cart, that either expands and/or telescopes into a compact size for storage or portability. The resulting size is a long, wide, narrow shape; usually limited in width by the distance between wheels, in thickness by the diameter of the wheels, and the length by the folded height of the handle.
If a chainbar is used as the adjustible legs of a camera tripod, the resulting tripod may be made into a more compact size, since a chainbar may be folded into smaller lengths. There is also no loss in space, since a chainbar does not require an overlap between its parts, as do telescoping tube legs, except for an anchoring device at the body end of the tripod. The chainbar could be made of hollow metal or plastic links to conserve weight and material, relying on the inherent structural strength of hollow members. Also, since the stress of the chainbar is distributed over a series of linkages, it could support more weight than friction locking devices, and could be made in a tapered shape.
If a chainbar is used in the design of a small luggage cart, the chainbar can be folded into a compact body, and used as the adjustible length handle, while the wheels may be mounted at the ends of a chainbar that also folds into the body, and can be extended away from the body for an increased wheelbase. Also, hinged flaps mounted on the top of the body, could be extended away from the body to provide a larger platform on which to put the luggage.
Some of the numerous uses that chainbars may be put to, include; microphone or music stands, curtain or towel rods with hook holes at the bottom length of the chainbar from which curtains, flags, signs, etc., may be hung, tents, umbrellas; folding tables or stools, luggage bags, and toys, such as.
Note that the chainbar could be made quite large, and used in construction equipment, for example; and that the smaller the links, the more circular the shape that the chainbar may be made to be regid in.
With holes in the individual links, through which flexible steel cables or electric power cables could be put through, the chainbar may be used in robotics, with the use of magnetic means for placing the links in the regid position, instead of mechanical means.